Association of Anti-Smith, Anti-Ro, and Anti-ribonucleoprotein Combination With Accelerated Development of Lupus Nephritis in Systemic Lupus Erythematosus Patients in Saudi Arabia

Abstract

Introduction: Systemic lupus erythematosus (SLE) is an autoimmune inflammatory disorder affecting multiple organs. Lupus nephritis (LN), one of its serious complications, is characterized by proteinuria and renal dysfunction. Objective: The objective of this study was to evaluate the association between a specific antibody profile (anti-Smith [anti-Sm], anti-Ro, and anti-ribonucleoprotein [anti-RNP]) and the time to develop LN in SLE patients. Methods: A retrospective, single-center cohort study was conducted at King Fahad Medical City (KFMC) in Riyadh, Saudi Arabia, and included 128 patients with LN who visited the Rheumatology Clinic between 2014 and 2021. Patients were divided into two groups: a positive serological profile group, which included patients positive for all three antibodies (anti-Sm, anti-Ro, and anti-RNP), and a negative serological profile group (which included patients with at least one negative antibody result). Data on demographics, antibody profiles, time to proteinuria development, and LN classification were analyzed. The time to develop proteinuria from the initial diagnosis of LN to the first detection of proteinuria exceeding 500 mg was categorized into less than 1 year, 1-5 years, 6-10 years, and more than 10 years. Results: Our findings revealed that a substantial proportion (95%) of patients positive for all three antibodies (anti-Sm, anti-Ro, and anti-RNP) had a significantly higher likelihood of developing proteinuria within the first five years of their SLE diagnosis, compared to 89.66% of patients with a negative serological profile. Conclusion: The findings suggest that the presence of anti-Sm, anti-Ro, and anti-RNP antibodies is associated with a higher risk of early LN development, specifically within five years after initial SLE diagnosis. Regular monitoring and proactive management of high-risk patients can reduce the burden of LN and its complications.